The Postmortem Pathology Section, along with the Cytopathology Section, Hematopathology Section, Surgical Pathology Section, and Ultrastructural Pathology Section, provides a complete service in Anatomic Pathology for the Clinical Center. In addition, when the use and study of human pathological material is requested by research staff of any of the institutes, the Postmortem Section makes every effort to collaborate with and/or supply the researchers with the human tissues upon approved request. The autopsy material is utilized by staff and residents for research projects involving clinicopathological correlation and characterization of disease processes. Currently, several projects are on-going: clinical-pathological studies in dementia; MRI correlations with normal tissue and de-myelinating disease (multiple sclerosis); experimental therapy of malignant brain tumors (both primary and metastatic); evaluation of cellular adhesion molecules involving organs in interleukin-2 treated individuals; normal ittuses used for purification of antigens to make antibodies; use of autopsy materials as quality control tissue for immunohistochemistry; distribution of HIV at the time of death; correlation of HIV disease/sequelae with quinolinic acid concentration in neural tissue; correlation of Candidal esophagitis with clinical information and retrospective review of disease in patients with Ewing's sarcomas or PNETs. A database of major autopsy findings from 1953 through the present is being compiled, with pertinent historical information included. The database is approximately 15-20% complete.